O3 production apparatus and exhaust gas purification system for internal combustion engine

Abstract

An object of the present invention is to produce O3 to be supplied to the exhaust gas of an internal combustion engine while suppressing deterioration of the fuel economy. An O3 production apparatus according to the present invention is an O3 production apparatus that produces O3 to be supplied to the exhaust gas of an internal combustion engine by generating a plasma, when the operation state of the internal combustion engine is a decelerating operation state in which the engine load becomes lower.

Description

TECHNICAL FIELD[0001]The present invention relates to an O3 production apparatus that produces O3 to be supplied to the exhaust gas of an internal combustion engine and to an exhaust gas purification system for an internal combustion engine.BACKGROUND ART[0002]An O3 production apparatus that produces O3 to be supplied to the exhaust gas of an internal combustion engine by generating a plasma has been known. Supply of O3 produced by such an O3 production apparatus to the exhaust gas promotes oxidation of NO in the exhaust gas, whereby NO can be changed into NO2. NO2 is stored more easily in an NOx storage reduction catalyst (which will be simply referred to as an “NOx catalyst” hereinafter) as compared to NO. Therefore, in the case where an NOx catalyst is provided in the exhaust passage of the internal combustion engine, changing NO in the exhaust gas into NO2 can promote storage of NOx in the NOx catalyst.[0003]Furthermore, in the case where a particulate filter (which will be simp...

AI Technical Summary

Benefits of technology

[0008]An object of the present invention is to provide a technology that enables production of O3 to be supplied to the exhaust gas of an internal combustion engine while suppressing deterioration of the fuel economy.[Means for Solving the Problem]

[0010]When the operation state of the internal combustion engine is a decelerating operation state, deterioration of the fuel economy is unlikely to occur even if electric power is consumed. Therefore, according to the present invention, it is possible to produce O3 to be supplied to the exhaust gas of the internal combustion engine while suppressing deterioration of the fuel economy.

[0012]Thus, when the present invention is applied to an internal combustion engine mounted on a hybrid vehicle, deterioration of the fuel economy can be further suppressed.

[0015]According to this, if the charge amount of the battery is not larger than the specific charge amount, electric power generated by the motor generator is supplied to the battery to increase the charge amount of the battery. Therefore, the charge amount of the battery can be prevented from becoming unduly small.

[0017]When the operation state of the internal combustion engine is an accelerating operation state, the quantity of NOx discharged from the internal combustion engine becomes larger, namely the quantity of NO in the exhaust gas becomes larger. By supplying O3 stored in the O3 storage apparatus to the exhaust gas flowing in the exhaust passage upstream of the NOx catalyst when the operation state of the internal combustion engine is an accelerating operation state, changing of NO, the quantity of which has increased, into NO2 is promoted. Thus, storage of NOx in the NOx catalyst can be promoted. Therefore, according to the above-described exhaust gas purification system, emission of NO to the atmosphere during the time when the operation state of the internal combustion engine is an accelerating operation state can be suppressed.

[0019]In view of the above, in the above-described exhaust gas purification system, the higher the increase rate of the engine load of the internal combustion engine is, or the lower the temperature of the NOx storage reduction catalyst is, the larger the quantity of O3 supplied to the exhaust gas may be made. The larger the quantity of O3 supplied to the exhaust gas is, the more changing of NO in the exhaust gas into NO2 is promoted. Therefore, according to the above feature, emission of NO to the atmosphere during the time when the operation state of the internal combustion engine is an accelerating operation state can be further suppressed.

Problems solved by technology

This may lead to deterioration of the fuel economy.

When the operation state of the internal combustion engine is a decelerating operation state, deterioration of the fuel economy is unlikely to occur even if electric power is consumed.

Images